The Ministry of Defence confirmed the flag 
will be lowered at all military establishments
The Spanish flag will fly at half-mast on all military buildings including the Ministry of Defence in Madrid to commemorate the death of Christ this Holy Week.
In a statement, the ministry said all units, bases, barracks will lower the flag from 2pm on Maundy Thursday to 12.01am on Easter Sunday “as is traditional”.
The ministry explained that the practice dates back several decades and “forms part of the secular tradition of the armed forces”.
The Spanish military will take part in 152 parades and celebrations to mark Holy Week in 80 cities across the country this year, including Seville, Granada, Madrid and the Canary Islands.
The Ministry of Defence highlighted the fact that freedom of religion for servicemen would be respected, and that participation by members of the armed forces at these events is voluntary.
http://www.catholicherald.co.uk/news/2018/03/28/spanish-flags-to-fly-at-half-mast-to-mark-death-of-christ/